Introduction

Atmosphere's composition :

Dinitrogen N2 78%

Oxygen O2 20%

Argon Ar 9%

Carbon dioxyde CO2 0,40% *

Water vapor H2O 0-3%

Cox, Arthur N., éd. 2002. Allen’s Astrophysical Quantities. 4eéd. New York : Springer-Verlag. https://doi.org/10.1007/978-1-4612-1186-0.

* "Vital signs: Carbon Dioxide". NASA Climate. May 2020. Retrieved 5 June 2020

Dinitrogen molecule

N2, the large amount of energy required to break the nitrogen-nitrogen triple bond makes this structure stable, which is why N2 is the most abundant in air.

Nitrogen reservoirs

Canfield, Donald E., Alexander N. Glazer, et Paul G. Falkowski. 2010. « The Evolution and Future of Earth’s Nitrogen Cycle ». Science 330 (6001): 192‐96.

https://doi.org/10.1126/science.1186120.

Nitrogen compounds

  • Ammonium NH4+

  • Nitrite NO2-

  • Nitrate NO3-

Why nitrogen is important to life ?

Hint : DNA

Medias